fix(schemas): add user tenantId foreign key constraint

[simeng-li]

Summary

We have identified a bug where developers can insert cross-tenant users into an organization using the POST /organizations/:id?users API. Previously, there was no constraint to ensure that a user's tenant_id matches the current organization's tenant_id.

To address this issue, we will add a foreign key constraint for the (tenant_id, user_id) in the organization_user_relations table.

Testing

test locally

Checklist

• [ ] .changeset
• [ ] unit tests
• [ ] integration tests
• [ ] necessary TSDoc comments